The invention concerns an exhaust gas bellows expansion joint for joining a first section and a second section of an exhaust pipe.
Those skilled in the art are familiar with the plain pipe joint for joining two sections of an exhaust pipe. In this type of pipe joint, a first section with a greater inside diameter is pushed over a second section. Due to the self-locking nature of the joint, additional fastening of the pipes to each other is not necessary. However, to ensure that self-locking occurs, it is necessary to provide suitably great overlapping of the sections. This results in a large overall length.
DE 35 39 778 C1 describes an exhaust pipe which is surrounded by a water-cooled jacket. An air gap is provided between the exhaust pipe and the jacket for thermal insulation. The junction of a first section with a second section of the exhaust pipe is designed as a plain pipe joint. The water passage from a first jacket to a second jacket is produced by a joint sleeve. However, to obtain effective joining of the sections of the exhaust pipe and the surrounding jacket, it is absolutely necessary to achieve exact positioning of the parts to be joined.
U.S. Pat. No. 2,014,355 describes an exhaust gas bellows expansion joint for connecting a first section and a second section of an exhaust pipe. This joint consists of an inner pipe for conveying the exhaust gas, a second pipe that concentrically surrounds the first pipe, and a flange at each end face for connecting the exhaust gas bellows expansion joint with a section of the exhaust pipe. The second pipe is radially spaced from the first pipe to form an annular space. The inner pipe consists of a first corrugated pipe, which is connected with the first flange, a second corrugated pipe, which is connected with the second flange, and a pipe length, which is located in a middle section between the first and second corrugated pipes. The surrounding second pipe is also designed as a corrugated pipe in this middle section. Cooling fluid is supplied to the annular space between the first and second pipes through a radial admission port in the area of the first flange. This cools the inner pipe. The cooling fluid is discharged through a radial discharge port in the area of the second flange. The exhaust gas bellows expansion joint described here has only limited applicability for an internal combustion engine with exhaust gas turbochargers, since energy is extracted from the exhaust gas by the cooling. This reduces the efficiency of an exhaust gas turbocharger.